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Add quaternion_look_at orientation procedure to package math/linalg

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gingerBill
2019-12-29 20:35:27 +00:00
parent a8a4dc1eb1
commit 2d70a784d1
1 changed files with 26 additions and 5 deletions
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core/math/linalg/specific.odin
+26 -5
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@@ -8,6 +8,8 @@ import "intrinsics"
Float :: f32; Float :: f32;
FLOAT_EPSILON :: size_of(Float) == 4 ? 1e-7 : 1e-15;
Vector2 :: distinct [2]Float; Vector2 :: distinct [2]Float;
Vector3 :: distinct [3]Float; Vector3 :: distinct [3]Float;
Vector4 :: distinct [4]Float; Vector4 :: distinct [4]Float;
@@ -51,6 +53,14 @@ VECTOR3_Y_AXIS :: Vector3{0, 1, 0};
VECTOR3_Z_AXIS :: Vector3{0, 0, 1}; VECTOR3_Z_AXIS :: Vector3{0, 0, 1};
radians :: proc(degrees: Float) -> Float {
return math.TAU * degrees / 360.0;
}
degrees :: proc(radians: Float) -> Float {
return 360.0 * radians / math.TAU;
}
vector2_orthogonal :: proc(v: Vector2) -> Vector2 { vector2_orthogonal :: proc(v: Vector2) -> Vector2 {
return {-v.y, v.x}; return {-v.y, v.x};
@@ -191,6 +201,20 @@ euler_angles_from_quaternion :: proc(q: Quaternion) -> (roll, pitch, yaw: Float)
return; return;
} }
quaternion_look_at :: proc(eye, centre: Vector3, up: Vector3) -> Quaternion {
f := normalize(centre - eye);
s := normalize(cross(f, up));
u := cross(s, f);
w := math.sqrt(1 + s.x + u.y - f.z)*0.5;
iw4 := 0.25/w;
x := (+u.z + f.y)*iw4;
y := (-f.x - s.z)*iw4;
z := (+s.y - u.x)*iw4;
q: Quaternion = quaternion(w, x, y, z);
return normalize(q);
}
quaternion_nlerp :: proc(a, b: Quaternion, t: Float) -> Quaternion { quaternion_nlerp :: proc(a, b: Quaternion, t: Float) -> Quaternion {
c := a + (b-a)*quaternion(t, 0, 0, 0); c := a + (b-a)*quaternion(t, 0, 0, 0);
@@ -199,7 +223,6 @@ quaternion_nlerp :: proc(a, b: Quaternion, t: Float) -> Quaternion {
quaternion_slerp :: proc(x, y: Quaternion, t: Float) -> Quaternion { quaternion_slerp :: proc(x, y: Quaternion, t: Float) -> Quaternion {
EPSILON :: size_of(Float) == 4 ? 1e-7 : 1e-15;
a, b := x, y; a, b := x, y;
cos_angle := dot(a, b); cos_angle := dot(a, b);
@@ -207,7 +230,7 @@ quaternion_slerp :: proc(x, y: Quaternion, t: Float) -> Quaternion {
b = -b; b = -b;
cos_angle = -cos_angle; cos_angle = -cos_angle;
} }
if cos_angle > 1 - EPSILON { if cos_angle > 1 - FLOAT_EPSILON {
return a + (b-a)*quaternion(t, 0, 0, 0); return a + (b-a)*quaternion(t, 0, 0, 0);
} }
@@ -290,13 +313,11 @@ quaternion_from_matrix4 :: proc(m: Matrix4) -> Quaternion {
quaternion_between_two_vector3 :: proc(from, to: Vector3) -> Quaternion { quaternion_between_two_vector3 :: proc(from, to: Vector3) -> Quaternion {
EPSILON :: size_of(Float) == 4 ? 1e-7 : 1e-15;
x := normalize(from); x := normalize(from);
y := normalize(to); y := normalize(to);
cos_theta := dot(x, y); cos_theta := dot(x, y);
if abs(cos_theta + 1) < 2*EPSILON { if abs(cos_theta + 1) < 2*FLOAT_EPSILON {
v := vector3_orthogonal(x); v := vector3_orthogonal(x);
return quaternion(0, v.x, v.y, v.z); return quaternion(0, v.x, v.y, v.z);
} }